It is known in the art to manufacture live conveyor roller pulleys substantially as shown in FIG. 1. In order to lubricate the motor and the gears in FIG. 1, a lubricant 100 is provided within the hollow of the pulley. However, in the space away from the motor and gear reducers, it has been found that the oil does not uniformly extend about the interior diameter and length of the pulley when the pulley is traveling at speeds less than the minimum speed (estimated to be approximately 0.75 meters per second) required to force the lubricant by centrifugal force against the inside wall of the pulley. Typically pulleys driving conveyor belts in supermarkets operate at 0.19 meters per second.
In use it has been found that the temperature of the pulley on the outside diameter of the roll tube is hottest in the location of the motor and gears and coolest at the other end of the pulley. The lubricant in the area where the motor and the gear reducers are not contained, stays relatively stationary at the bottom of the pulley at a speeds below 0.75 meters per second, as shown in FIG. 1.
It has been found that conveyor belts running around such pulleys as described above, are continually in need of adjustment as they tend to go out of alignment easily. For example, a conveyor belt running around a pulley as illustrated in FIG. 1, will tend to stretch or expand around the perimeter of the pulley proximate end A in relation to end B. It has been determined that the conveyor belt in fact has much of the heat generated by the pulley, passed on to the material making up the conveyor belt. Therefore a conveyor belt running around area A will tend to stretch because of the increased heat available to the conveyor belt at end A in relation to end B. The conveyor belt will then have a tendency to go easily out Of alignment because of the temperature differential across the conveyor belt.
It will therefore be advantageous to provide a live conveyor pulley which would have a uniform temperature distribution across the length thereof, to ensure in use that the conveyor belt would have substantially the same temperature across its width during start up of the conveyor belt and during the continued operation of the conveyor belt. Such an advantage would result in an overall lower temperature on the pulley surface and belt, less adjustment of the belt and would result in a longer life for the conveyor belt.
To the best of Applicant's knowledge, nowhere in the prior art is there found a device for ensuring the uniform temperature distribution of the conveyor roller and hence the conveyor belt.
It is therefore a primary object of this invention to provide a live pulley for a conveyor belt which provides for the substantial uniform distribution of the temperature across the ends of the pulley.
It is a further object of this invention to provide various mechanisms which will accomplish the primary object of the invention, which may be contained within the drive pulley.
Further and other objects of the invention will become apparent to those skilled in the art when considering the following summary invention and the more detailed description of the preferred embodiments illustrated herein.